<berndj>
heh, "shrink to the 12.5µ node" has surely not been heard in 30 years
<Sync>
:D
<berndj>
azonenberg, what will you do about contacts? won't you need to futz with tungsten and the like?
<berndj>
Sync: how's your grasp on thermodynamics?
<azonenberg>
berndj: unknown at this point
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<azonenberg>
My first goal is to get litho working reliably at the 12.5um node
<azonenberg>
once i can do patterning, i'll take it from there
<Sync>
berndj: first rule of thermodynamics, you do not talk about thermodynamics
<berndj>
that must be the -1th law :)
<Sync>
what's the problem?
<berndj>
joule expansion. besides eliminating moving parts, what's the advantage?
<berndj>
isn't adiabatic expansion hugely more efficient?
<berndj>
you're the one working on DIY cryo, aren't you?
<Sync>
yes
<Sync>
yes adibatic expansion is more efficient but it has drawbacks
<berndj>
for a small liquefier it's no issue of course, you go for the fewest-moving-parts method. but if you're doing tonnes a day i'd expect energy costs to start mattering
<Sync>
I'm currently waiting for some gasses to arrive then I can investigate some autocascading systems
<Sync>
yes but then your are doing it differently
<Sync>
bah -r
<berndj>
actually i though J-T expansion was how the commercial air separation plants worked. i may be mistaken
<Sync>
that depends
<Sync>
there are some that use adibatic expansion
<Sync>
but yes the majority ist J-T
<berndj>
maybe the plant predates the green revolution
<Sync>
I guess the idea is to have highly optimized compressors for your load
<Sync>
also most processes are low pressure now
<berndj>
ah. i can see adiabatic expansion being a lot more sensitive to load variations than a J-T system
<berndj>
you're [going to be] running at ~100bar IIRC/
<berndj>
s,/,?,
<Sync>
yes, but plans are slowly changing
<Sync>
the cascade cooling system is far too large if I run at that pressure
<Sync>
I can get much smaller with advanced cooling concepts
<berndj>
why was it necessary to run at such a high pressure in the first place?
<berndj>
is the cooling just plain not enough at lower pressure?
<Sync>
because you need a high pressure differential to get enough temperature drop
<berndj>
in general, or to have a system that can start up? (as µ rises as air gets cooler)
<Sync>
that is a good question
<Sync>
I do not know how startup in larger air destillation plants works
<Sync>
I'd say they prime them
<berndj>
classic bootstrap problem
<Sync>
I now plan to run the N2 at something managable like 25bar but chill it using an autocascading system
<Sync>
thus eliminating the need for huge compressors
<Sync>
but that is a long term project now that I have LN2 on tap
<berndj>
if you cool air, do you get a mixture of N2 and O2, or one or the other, or what?
<Sync>
you get a mixture
<Sync>
and you need to destill the o2 off
<berndj>
i'm still not 100% confident of my reasoning in the answer i gave to that Q
<Sync>
also most dewars are capped off when filled
<berndj>
distillation, yet another major project
<Sync>
so they have a ever so slight amount of nitrogen coming out
<Sync>
that replaces all oxygen
<Sync>
you can indeed make LO2 with LN2 :P
<Sync>
been there done that
<Sync>
fun stuff
<berndj>
just using the LN2 as heat sink to condense the O2?
<Sync>
yes
<berndj>
that's what i'm unsure about in my Q; the way i read O2's vapour pressure graph, it only just starts to condense out of air at LN2's boiling point
<berndj>
*in my A to that Q
<Sync>
just look at the standard condition points
<berndj>
yeah, then it's 90K as opposed to N2's 77K
<berndj>
but oxygen isn't at 1atm in the air
<Sync>
I'm not so sure if the PPO2 is important there
<Sync>
for condensing out O2 from the air probably, but for liquifiying O2 from the bottle not so much
<berndj>
well, the ambient temperature is under 100C, yet it isn't raining
<berndj>
ah, sure, out of the bottle it'd be at or (way) above 1atm
<Sync>
I think you are right, the BP at the PPO2 in air is so close to the BP of N2 that it barely condenses out
<berndj>
i guess that's why you get a mixture when you liquefy air
<Sync>
no
<Sync>
that is just because you have both gasses in the air
<Sync>
the pressure differential is enough to liquify both
<berndj>
if PPO2 were a bit higher, you'd first get O2 condensing out though, wouldn't you?
<Sync>
gah I should go to sleep
<berndj>
i guess it depends on just how big the T drop is in the expansion
<Sync>
when I'm liquifying air the PPO2 just determines what I end up with
<Sync>
condensing out from the air is different
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